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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 58 (Engine Cooling) >> Repair Instructions >> Cooling System Draining and Filling (Vac-N-Fill) >> Vac-N-Fill Procedure

Vac-N-Fill Procedure

WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: To prevent boiling of the coolant/water mixture in the vehicles cooling system, do not apply vacuum to a cooling system above 49°C (120°F). The tool will not operate properly when the coolant is boiling.
  1. Install the J 42401 .
    Fig 1: Identifying Vac-N-Fill Cap
    GM1617435Courtesy of GENERAL MOTORS CORP.
  2. Attach the Vac-N-Fill cap to the vehicles coolant fill port.
    Fig 2: Attaching The Vacuum Gage Assembly To The Vac-N-Fill Cap
    GM1617436Courtesy of GENERAL MOTORS CORP.
  3. Attach the vacuum gage assembly to the Vac-N-Fill cap.
    Fig 3: Attaching Fill Hose To Barb Fitting On Vacuum Gage Assembly
    GM1617437Courtesy of GENERAL MOTORS CORP.
  4. Attach the fill hose to the barb fitting on the vacuum gage assembly. Ensure that the valve is closed.
    Fig 4: View Of Graduated Reservoir & Hose
    GM1617438Courtesy of GENERAL MOTORS CORP.
    IMPORTANT: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water. Always use more coolant than necessary. This will eliminate air from being drawn into the cooling system.
  5. Pour the coolant mixture into the graduated reservoir.
  6. Place the fill hose in the graduated reservoir.
    IMPORTANT: Prior to installing the vacuum tank onto the graduated reservoir, ensure that the drain valve located on the bottom of the tank is closed.
  7. Install the vacuum tank on the graduated reservoir with the fill hose routed through the cut-out area in the vacuum tank.
    Fig 5: Connecting Venturi Assembly To Vacuum Tank
    GM1617439Courtesy of GENERAL MOTORS CORP.
  8. Attach the venturi assembly to the vacuum tank.
    Fig 6: Attaching Shop Air Hose To Venturi Assembly
    GM1617440Courtesy of GENERAL MOTORS CORP.
  9. Attach a shop air hose to the venture assembly. Ensure the valve on the venture assembly is closed.
    Fig 7: Attaching Vacuum Hose To Vacuum Gauge Assembly & Vacuum Tank
    GM1617441Courtesy of GENERAL MOTORS CORP.
  10. Attach the vacuum hose to the vacuum gage assembly and the vacuum tank.
  11. Clamp off the overflow hose.
    Fig 8: Identifying Valve On Venturi Assembly
    GM1617442Courtesy of GENERAL MOTORS CORP.
  12. Open the valve on the venture assembly. The vacuum gage will begin to rise and a hissing noise will be present.
    Fig 9: View Of Vacuum Gauge
    GM1617443Courtesy of GENERAL MOTORS CORP.
  13. Continue to draw vacuum until the needle stops rising. This should be 610-660 mm Hg (24-26 in Hg). Cooling hoses may start to collapse. This is normal due to vacuum draw.
  14. To aid in the fill process, position the graduated reservoir above the coolant fill port.
    Fig 10: Identifying Valve On Vacuum Gage Assembly
    GM1617446Courtesy of GENERAL MOTORS CORP.
  15. Slowly open the valve on the vacuum gage assembly. When the coolant reaches the top of the fill hose, close the valve. This will eliminate air from the fill hose.
  16. Close the valve on the venture assembly. If vacuum loss is observed, refer to Loss of Coolant  .
  17. If there is a suspected leak in the cooling system, allow the system to stabilize under vacuum and monitor for vacuum loss.

    If vacuum loss is observed, refer to Loss of Coolant  .

  18. Open the valve on the vacuum gage assembly. The vacuum gage will drop as coolant is drawn into the system.
    Fig 11: View Of Vacuum Gauge & Radiator
    GM1617448Courtesy of GENERAL MOTORS CORP.
  19. Once the vacuum gage reaches zero, close the valve on the vacuum gage assembly and repeat steps 11-17.
  20. Remove the J 42401 .
  21. Detach the Vac-N-Fill cap from the vehicles coolant fill port.
  22. Add coolant to the system as necessary.
  23. Inspect the concentration of the coolant mixture using J 26568 .
    IMPORTANT: After filling the cooling system, the extraction hose can be used to remove excess coolant to achieve the proper coolant level.
  24. Detach the vacuum hose from the vacuum gage assembly.
    Fig 12: Attaching Extraction Hose To Vacuum Hose
    GM1617450Courtesy of GENERAL MOTORS CORP.
  25. Attach the extraction hose to the vacuum hose.
    Fig 13: Identifying Valve On Venturi Assembly
    GM1617453Courtesy of GENERAL MOTORS CORP.
  26. Open the valve on the venturi assembly to start a vacuum draw.
    Fig 14: Using Extraction Hose To Draw Out Coolant
    GM1617456Courtesy of GENERAL MOTORS CORP.
  27. Use the extraction hose to draw out coolant to the proper level.
  28. The vacuum tank has a drain valve on the bottom of the tank. Open the valve to drain coolant from the vacuum tank into a suitable container for disposal.